Les Diaboliques (1954) is a black-and-white film directed by Henri-Georges Clouzot, starring Simone Signoret and Véra Clouzot. The title translates as 'The Devils'. In the US release it was titled Diabolique. It is based on the novel Celle qui n'était plus (She Who Was No More) by Pierre Boileau and Thomas Narcejac.
The film created a sensation on its original release. It has often been likened to the films of Alfred Hitchcock in that it is still creepy even when one has seen it and knows the ending. (Many sources say that Alfred Hitchcock missed out on purchasing the rights to the Boileau and Narcejac novel by just a few hours, Clouzot getting to the authors first.) The end credit contains an early example of an "anti-spoiler message", requesting the audience not to disclose the plot to others who have not seen the film.
In a French provincial town, Michel Delassalle, a sadistic headmaster of a school belonging to his wife Christina, a fragile young woman with a weak heart, carries on an affair with Nicole Horner, a strong, forceful teacher who has been his mistress from the day she arrived. He has, however, treated her as badly as his wife, and the two women have been driven into an alliance against him. Together they work out an elaborate plan to rid themselves of their common tormentor. Luring him away from the school to Nocole's cheap lodging house, they induce him to drink some doctored whiskey - and drown him in a bath. The body is later wrapped in a nylon tablecloth, packed into a laundry basket, taken back to the school, and at dark tipped into the grimy water of the school swimming pool. When, shortly after, the pool is drained, watched in anguished expectation from a window by the women, no corpse is there.